fs/ext4/resize.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  linux/fs/ext4/resize.c
   4  *
   5  * Support for resizing an ext4 filesystem while it is mounted.
   6  *
   7  * Copyright (C) 2001, 2002 Andreas Dilger <adilger@clusterfs.com>
   8  *
   9  * This could probably be made into a module, because it is not often in use.
  10  */
  11
  12
  13 #define EXT4FS_DEBUG
  14
  15 #include <linux/errno.h>
  16 #include <linux/slab.h>
  17
  18 #include "ext4_jbd2.h"
  19
  20 int ext4_resize_begin(struct super_block *sb)
  21 {
  22         struct ext4_sb_info *sbi = EXT4_SB(sb);
  23         int ret = 0;
  24
  25         if (!capable(CAP_SYS_RESOURCE))
  26                 return -EPERM;
  27
  28         /*
  29          * If we are not using the primary superblock/GDT copy don't resize,
  30          * because the user tools have no way of handling this.  Probably a
  31          * bad time to do it anyways.
  32          */
  33         if (EXT4_B2C(sbi, sbi->s_sbh->b_blocknr) !=
  34             le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) {
  35                 ext4_warning(sb, "won't resize using backup superblock at %llu",
  36                         (unsigned long long)EXT4_SB(sb)->s_sbh->b_blocknr);
  37                 return -EPERM;
  38         }
  39
  40         /*
  41          * We are not allowed to do online-resizing on a filesystem mounted
  42          * with error, because it can destroy the filesystem easily.
  43          */
  44         if (EXT4_SB(sb)->s_mount_state & EXT4_ERROR_FS) {
  45                 ext4_warning(sb, "There are errors in the filesystem, "
  46                              "so online resizing is not allowed");
  47                 return -EPERM;
  48         }
  49
  50         if (test_and_set_bit_lock(EXT4_FLAGS_RESIZING,
  51                                   &EXT4_SB(sb)->s_ext4_flags))
  52                 ret = -EBUSY;
  53
  54         return ret;
  55 }
  56
  57 void ext4_resize_end(struct super_block *sb)
  58 {
  59         clear_bit_unlock(EXT4_FLAGS_RESIZING, &EXT4_SB(sb)->s_ext4_flags);
  60         smp_mb__after_atomic();
  61 }
  62
  63 static ext4_group_t ext4_meta_bg_first_group(struct super_block *sb,
  64                                              ext4_group_t group) {
  65         return (group >> EXT4_DESC_PER_BLOCK_BITS(sb)) <<
  66                EXT4_DESC_PER_BLOCK_BITS(sb);
  67 }
  68
  69 static ext4_fsblk_t ext4_meta_bg_first_block_no(struct super_block *sb,
  70                                              ext4_group_t group) {
  71         group = ext4_meta_bg_first_group(sb, group);
  72         return ext4_group_first_block_no(sb, group);
  73 }
  74
  75 static ext4_grpblk_t ext4_group_overhead_blocks(struct super_block *sb,
  76                                                 ext4_group_t group) {
  77         ext4_grpblk_t overhead;
  78         overhead = ext4_bg_num_gdb(sb, group);
  79         if (ext4_bg_has_super(sb, group))
  80                 overhead += 1 +
  81                           le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
  82         return overhead;
  83 }
  84
  85 #define outside(b, first, last) ((b) < (first) || (b) >= (last))
  86 #define inside(b, first, last)  ((b) >= (first) && (b) < (last))
  87
  88 static int verify_group_input(struct super_block *sb,
  89                               struct ext4_new_group_data *input)
  90 {
  91         struct ext4_sb_info *sbi = EXT4_SB(sb);
  92         struct ext4_super_block *es = sbi->s_es;
  93         ext4_fsblk_t start = ext4_blocks_count(es);
  94         ext4_fsblk_t end = start + input->blocks_count;
  95         ext4_group_t group = input->group;
  96         ext4_fsblk_t itend = input->inode_table + sbi->s_itb_per_group;
  97         unsigned overhead;
  98         ext4_fsblk_t metaend;
  99         struct buffer_head *bh = NULL;
 100         ext4_grpblk_t free_blocks_count, offset;
 101         int err = -EINVAL;
 102
 103         if (group != sbi->s_groups_count) {
 104                 ext4_warning(sb, "Cannot add at group %u (only %u groups)",
 105                              input->group, sbi->s_groups_count);
 106                 return -EINVAL;
 107         }
 108
 109         overhead = ext4_group_overhead_blocks(sb, group);
 110         metaend = start + overhead;
 111         input->free_clusters_count = free_blocks_count =
 112                 input->blocks_count - 2 - overhead - sbi->s_itb_per_group;
 113
 114         if (test_opt(sb, DEBUG))
 115                 printk(KERN_DEBUG "EXT4-fs: adding %s group %u: %u blocks "
 116                        "(%d free, %u reserved)\n",
 117                        ext4_bg_has_super(sb, input->group) ? "normal" :
 118                        "no-super", input->group, input->blocks_count,
 119                        free_blocks_count, input->reserved_blocks);
 120
 121         ext4_get_group_no_and_offset(sb, start, NULL, &offset);
 122         if (offset != 0)
 123                         ext4_warning(sb, "Last group not full");
 124         else if (input->reserved_blocks > input->blocks_count / 5)
 125                 ext4_warning(sb, "Reserved blocks too high (%u)",
 126                              input->reserved_blocks);
 127         else if (free_blocks_count < 0)
 128                 ext4_warning(sb, "Bad blocks count %u",
 129                              input->blocks_count);
 130         else if (!(bh = sb_bread(sb, end - 1)))
 131                 ext4_warning(sb, "Cannot read last block (%llu)",
 132                              end - 1);
 133         else if (outside(input->block_bitmap, start, end))
 134                 ext4_warning(sb, "Block bitmap not in group (block %llu)",
 135                              (unsigned long long)input->block_bitmap);
 136         else if (outside(input->inode_bitmap, start, end))
 137                 ext4_warning(sb, "Inode bitmap not in group (block %llu)",
 138                              (unsigned long long)input->inode_bitmap);
 139         else if (outside(input->inode_table, start, end) ||
 140                  outside(itend - 1, start, end))
 141                 ext4_warning(sb, "Inode table not in group (blocks %llu-%llu)",
 142                              (unsigned long long)input->inode_table, itend - 1);
 143         else if (input->inode_bitmap == input->block_bitmap)
 144                 ext4_warning(sb, "Block bitmap same as inode bitmap (%llu)",
 145                              (unsigned long long)input->block_bitmap);
 146         else if (inside(input->block_bitmap, input->inode_table, itend))
 147                 ext4_warning(sb, "Block bitmap (%llu) in inode table "
 148                              "(%llu-%llu)",
 149                              (unsigned long long)input->block_bitmap,
 150                              (unsigned long long)input->inode_table, itend - 1);
 151         else if (inside(input->inode_bitmap, input->inode_table, itend))
 152                 ext4_warning(sb, "Inode bitmap (%llu) in inode table "
 153                              "(%llu-%llu)",
 154                              (unsigned long long)input->inode_bitmap,
 155                              (unsigned long long)input->inode_table, itend - 1);
 156         else if (inside(input->block_bitmap, start, metaend))
 157                 ext4_warning(sb, "Block bitmap (%llu) in GDT table (%llu-%llu)",
 158                              (unsigned long long)input->block_bitmap,
 159                              start, metaend - 1);
 160         else if (inside(input->inode_bitmap, start, metaend))
 161                 ext4_warning(sb, "Inode bitmap (%llu) in GDT table (%llu-%llu)",
 162                              (unsigned long long)input->inode_bitmap,
 163                              start, metaend - 1);
 164         else if (inside(input->inode_table, start, metaend) ||
 165                  inside(itend - 1, start, metaend))
 166                 ext4_warning(sb, "Inode table (%llu-%llu) overlaps GDT table "
 167                              "(%llu-%llu)",
 168                              (unsigned long long)input->inode_table,
 169                              itend - 1, start, metaend - 1);
 170         else
 171                 err = 0;
 172         brelse(bh);
 173
 174         return err;
 175 }
 176
 177 /*
 178  * ext4_new_flex_group_data is used by 64bit-resize interface to add a flex
 179  * group each time.
 180  */
 181 struct ext4_new_flex_group_data {
 182         struct ext4_new_group_data *groups;     /* new_group_data for groups
 183                                                    in the flex group */
 184         __u16 *bg_flags;                        /* block group flags of groups
 185                                                    in @groups */
 186         ext4_group_t count;                     /* number of groups in @groups
 187                                                  */
 188 };
 189
 190 /*
 191  * alloc_flex_gd() allocates a ext4_new_flex_group_data with size of
 192  * @flexbg_size.
 193  *
 194  * Returns NULL on failure otherwise address of the allocated structure.
 195  */
 196 static struct ext4_new_flex_group_data *alloc_flex_gd(unsigned long flexbg_size)
 197 {
 198         struct ext4_new_flex_group_data *flex_gd;
 199
 200         flex_gd = kmalloc(sizeof(*flex_gd), GFP_NOFS);
 201         if (flex_gd == NULL)
 202                 goto out3;
 203
 204         if (flexbg_size >= UINT_MAX / sizeof(struct ext4_new_group_data))
 205                 goto out2;
 206         flex_gd->count = flexbg_size;
 207
 208         flex_gd->groups = kmalloc_array(flexbg_size,
 209                                         sizeof(struct ext4_new_group_data),
 210                                         GFP_NOFS);
 211         if (flex_gd->groups == NULL)
 212                 goto out2;
 213
 214         flex_gd->bg_flags = kmalloc_array(flexbg_size, sizeof(__u16),
 215                                           GFP_NOFS);
 216         if (flex_gd->bg_flags == NULL)
 217                 goto out1;
 218
 219         return flex_gd;
 220
 221 out1:
 222         kfree(flex_gd->groups);
 223 out2:
 224         kfree(flex_gd);
 225 out3:
 226         return NULL;
 227 }
 228
 229 static void free_flex_gd(struct ext4_new_flex_group_data *flex_gd)
 230 {
 231         kfree(flex_gd->bg_flags);
 232         kfree(flex_gd->groups);
 233         kfree(flex_gd);
 234 }
 235
 236 /*
 237  * ext4_alloc_group_tables() allocates block bitmaps, inode bitmaps
 238  * and inode tables for a flex group.
 239  *
 240  * This function is used by 64bit-resize.  Note that this function allocates
 241  * group tables from the 1st group of groups contained by @flexgd, which may
 242  * be a partial of a flex group.
 243  *
 244  * @sb: super block of fs to which the groups belongs
 245  *
 246  * Returns 0 on a successful allocation of the metadata blocks in the
 247  * block group.
 248  */
 249 static int ext4_alloc_group_tables(struct super_block *sb,
 250                                 struct ext4_new_flex_group_data *flex_gd,
 251                                 int flexbg_size)
 252 {
 253         struct ext4_new_group_data *group_data = flex_gd->groups;
 254         ext4_fsblk_t start_blk;
 255         ext4_fsblk_t last_blk;
 256         ext4_group_t src_group;
 257         ext4_group_t bb_index = 0;
 258         ext4_group_t ib_index = 0;
 259         ext4_group_t it_index = 0;
 260         ext4_group_t group;
 261         ext4_group_t last_group;
 262         unsigned overhead;
 263         __u16 uninit_mask = (flexbg_size > 1) ? ~EXT4_BG_BLOCK_UNINIT : ~0;
 264         int i;
 265
 266         BUG_ON(flex_gd->count == 0 || group_data == NULL);
 267
 268         src_group = group_data[0].group;
 269         last_group  = src_group + flex_gd->count - 1;
 270
 271         BUG_ON((flexbg_size > 1) && ((src_group & ~(flexbg_size - 1)) !=
 272                (last_group & ~(flexbg_size - 1))));
 273 next_group:
 274         group = group_data[0].group;
 275         if (src_group >= group_data[0].group + flex_gd->count)
 276                 return -ENOSPC;
 277         start_blk = ext4_group_first_block_no(sb, src_group);
 278         last_blk = start_blk + group_data[src_group - group].blocks_count;
 279
 280         overhead = ext4_group_overhead_blocks(sb, src_group);
 281
 282         start_blk += overhead;
 283
 284         /* We collect contiguous blocks as much as possible. */
 285         src_group++;
 286         for (; src_group <= last_group; src_group++) {
 287                 overhead = ext4_group_overhead_blocks(sb, src_group);
 288                 if (overhead == 0)
 289                         last_blk += group_data[src_group - group].blocks_count;
 290                 else
 291                         break;
 292         }
 293
 294         /* Allocate block bitmaps */
 295         for (; bb_index < flex_gd->count; bb_index++) {
 296                 if (start_blk >= last_blk)
 297                         goto next_group;
 298                 group_data[bb_index].block_bitmap = start_blk++;
 299                 group = ext4_get_group_number(sb, start_blk - 1);
 300                 group -= group_data[0].group;
 301                 group_data[group].mdata_blocks++;
 302                 flex_gd->bg_flags[group] &= uninit_mask;
 303         }
 304
 305         /* Allocate inode bitmaps */
 306         for (; ib_index < flex_gd->count; ib_index++) {
 307                 if (start_blk >= last_blk)
 308                         goto next_group;
 309                 group_data[ib_index].inode_bitmap = start_blk++;
 310                 group = ext4_get_group_number(sb, start_blk - 1);
 311                 group -= group_data[0].group;
 312                 group_data[group].mdata_blocks++;
 313                 flex_gd->bg_flags[group] &= uninit_mask;
 314         }
 315
 316         /* Allocate inode tables */
 317         for (; it_index < flex_gd->count; it_index++) {
 318                 unsigned int itb = EXT4_SB(sb)->s_itb_per_group;
 319                 ext4_fsblk_t next_group_start;
 320
 321                 if (start_blk + itb > last_blk)
 322                         goto next_group;
 323                 group_data[it_index].inode_table = start_blk;
 324                 group = ext4_get_group_number(sb, start_blk);
 325                 next_group_start = ext4_group_first_block_no(sb, group + 1);
 326                 group -= group_data[0].group;
 327
 328                 if (start_blk + itb > next_group_start) {
 329                         flex_gd->bg_flags[group + 1] &= uninit_mask;
 330                         overhead = start_blk + itb - next_group_start;
 331                         group_data[group + 1].mdata_blocks += overhead;
 332                         itb -= overhead;
 333                 }
 334
 335                 group_data[group].mdata_blocks += itb;
 336                 flex_gd->bg_flags[group] &= uninit_mask;
 337                 start_blk += EXT4_SB(sb)->s_itb_per_group;
 338         }
 339
 340         /* Update free clusters count to exclude metadata blocks */
 341         for (i = 0; i < flex_gd->count; i++) {
 342                 group_data[i].free_clusters_count -=
 343                                 EXT4_NUM_B2C(EXT4_SB(sb),
 344                                              group_data[i].mdata_blocks);
 345         }
 346
 347         if (test_opt(sb, DEBUG)) {
 348                 int i;
 349                 group = group_data[0].group;
 350
 351                 printk(KERN_DEBUG "EXT4-fs: adding a flex group with "
 352                        "%d groups, flexbg size is %d:\n", flex_gd->count,
 353                        flexbg_size);
 354
 355                 for (i = 0; i < flex_gd->count; i++) {
 356                         ext4_debug(
 357                                "adding %s group %u: %u blocks (%d free, %d mdata blocks)\n",
 358                                ext4_bg_has_super(sb, group + i) ? "normal" :
 359                                "no-super", group + i,
 360                                group_data[i].blocks_count,
 361                                group_data[i].free_clusters_count,
 362                                group_data[i].mdata_blocks);
 363                 }
 364         }
 365         return 0;
 366 }
 367
 368 static struct buffer_head *bclean(handle_t *handle, struct super_block *sb,
 369                                   ext4_fsblk_t blk)
 370 {
 371         struct buffer_head *bh;
 372         int err;
 373
 374         bh = sb_getblk(sb, blk);
 375         if (unlikely(!bh))
 376                 return ERR_PTR(-ENOMEM);
 377         BUFFER_TRACE(bh, "get_write_access");
 378         if ((err = ext4_journal_get_write_access(handle, bh))) {
 379                 brelse(bh);
 380                 bh = ERR_PTR(err);
 381         } else {
 382                 memset(bh->b_data, 0, sb->s_blocksize);
 383                 set_buffer_uptodate(bh);
 384         }
 385
 386         return bh;
 387 }
 388
 389 /*
 390  * If we have fewer than thresh credits, extend by EXT4_MAX_TRANS_DATA.
 391  * If that fails, restart the transaction & regain write access for the
 392  * buffer head which is used for block_bitmap modifications.
 393  */
 394 static int extend_or_restart_transaction(handle_t *handle, int thresh)
 395 {
 396         int err;
 397
 398         if (ext4_handle_has_enough_credits(handle, thresh))
 399                 return 0;
 400
 401         err = ext4_journal_extend(handle, EXT4_MAX_TRANS_DATA);
 402         if (err < 0)
 403                 return err;
 404         if (err) {
 405                 err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA);
 406                 if (err)
 407                         return err;
 408         }
 409
 410         return 0;
 411 }
 412
 413 /*
 414  * set_flexbg_block_bitmap() mark clusters [@first_cluster, @last_cluster] used.
 415  *
 416  * Helper function for ext4_setup_new_group_blocks() which set .
 417  *
 418  * @sb: super block
 419  * @handle: journal handle
 420  * @flex_gd: flex group data
 421  */
 422 static int set_flexbg_block_bitmap(struct super_block *sb, handle_t *handle,
 423                         struct ext4_new_flex_group_data *flex_gd,
 424                         ext4_fsblk_t first_cluster, ext4_fsblk_t last_cluster)
 425 {
 426         struct ext4_sb_info *sbi = EXT4_SB(sb);
 427         ext4_group_t count = last_cluster - first_cluster + 1;
 428         ext4_group_t count2;
 429
 430         ext4_debug("mark clusters [%llu-%llu] used\n", first_cluster,
 431                    last_cluster);
 432         for (count2 = count; count > 0;
 433              count -= count2, first_cluster += count2) {
 434                 ext4_fsblk_t start;
 435                 struct buffer_head *bh;
 436                 ext4_group_t group;
 437                 int err;
 438
 439                 group = ext4_get_group_number(sb, EXT4_C2B(sbi, first_cluster));
 440                 start = EXT4_B2C(sbi, ext4_group_first_block_no(sb, group));
 441                 group -= flex_gd->groups[0].group;
 442
 443                 count2 = EXT4_CLUSTERS_PER_GROUP(sb) - (first_cluster - start);
 444                 if (count2 > count)
 445                         count2 = count;
 446
 447                 if (flex_gd->bg_flags[group] & EXT4_BG_BLOCK_UNINIT) {
 448                         BUG_ON(flex_gd->count > 1);
 449                         continue;
 450                 }
 451
 452                 err = extend_or_restart_transaction(handle, 1);
 453                 if (err)
 454                         return err;
 455
 456                 bh = sb_getblk(sb, flex_gd->groups[group].block_bitmap);
 457                 if (unlikely(!bh))
 458                         return -ENOMEM;
 459
 460                 BUFFER_TRACE(bh, "get_write_access");
 461                 err = ext4_journal_get_write_access(handle, bh);
 462                 if (err) {
 463                         brelse(bh);
 464                         return err;
 465                 }
 466                 ext4_debug("mark block bitmap %#04llx (+%llu/%u)\n",
 467                            first_cluster, first_cluster - start, count2);
 468                 ext4_set_bits(bh->b_data, first_cluster - start, count2);
 469
 470                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
 471                 brelse(bh);
 472                 if (unlikely(err))
 473                         return err;
 474         }
 475
 476         return 0;
 477 }
 478
 479 /*
 480  * Set up the block and inode bitmaps, and the inode table for the new groups.
 481  * This doesn't need to be part of the main transaction, since we are only
 482  * changing blocks outside the actual filesystem.  We still do journaling to
 483  * ensure the recovery is correct in case of a failure just after resize.
 484  * If any part of this fails, we simply abort the resize.
 485  *
 486  * setup_new_flex_group_blocks handles a flex group as follow:
 487  *  1. copy super block and GDT, and initialize group tables if necessary.
 488  *     In this step, we only set bits in blocks bitmaps for blocks taken by
 489  *     super block and GDT.
 490  *  2. allocate group tables in block bitmaps, that is, set bits in block
 491  *     bitmap for blocks taken by group tables.
 492  */
 493 static int setup_new_flex_group_blocks(struct super_block *sb,
 494                                 struct ext4_new_flex_group_data *flex_gd)
 495 {
 496         int group_table_count[] = {1, 1, EXT4_SB(sb)->s_itb_per_group};
 497         ext4_fsblk_t start;
 498         ext4_fsblk_t block;
 499         struct ext4_sb_info *sbi = EXT4_SB(sb);
 500         struct ext4_super_block *es = sbi->s_es;
 501         struct ext4_new_group_data *group_data = flex_gd->groups;
 502         __u16 *bg_flags = flex_gd->bg_flags;
 503         handle_t *handle;
 504         ext4_group_t group, count;
 505         struct buffer_head *bh = NULL;
 506         int reserved_gdb, i, j, err = 0, err2;
 507         int meta_bg;
 508
 509         BUG_ON(!flex_gd->count || !group_data ||
 510                group_data[0].group != sbi->s_groups_count);
 511
 512         reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
 513         meta_bg = ext4_has_feature_meta_bg(sb);
 514
 515         /* This transaction may be extended/restarted along the way */
 516         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, EXT4_MAX_TRANS_DATA);
 517         if (IS_ERR(handle))
 518                 return PTR_ERR(handle);
 519
 520         group = group_data[0].group;
 521         for (i = 0; i < flex_gd->count; i++, group++) {
 522                 unsigned long gdblocks;
 523                 ext4_grpblk_t overhead;
 524
 525                 gdblocks = ext4_bg_num_gdb(sb, group);
 526                 start = ext4_group_first_block_no(sb, group);
 527
 528                 if (meta_bg == 0 && !ext4_bg_has_super(sb, group))
 529                         goto handle_itb;
 530
 531                 if (meta_bg == 1) {
 532                         ext4_group_t first_group;
 533                         first_group = ext4_meta_bg_first_group(sb, group);
 534                         if (first_group != group + 1 &&
 535                             first_group != group + EXT4_DESC_PER_BLOCK(sb) - 1)
 536                                 goto handle_itb;
 537                 }
 538
 539                 block = start + ext4_bg_has_super(sb, group);
 540                 /* Copy all of the GDT blocks into the backup in this group */
 541                 for (j = 0; j < gdblocks; j++, block++) {
 542                         struct buffer_head *gdb;
 543
 544                         ext4_debug("update backup group %#04llx\n", block);
 545                         err = extend_or_restart_transaction(handle, 1);
 546                         if (err)
 547                                 goto out;
 548
 549                         gdb = sb_getblk(sb, block);
 550                         if (unlikely(!gdb)) {
 551                                 err = -ENOMEM;
 552                                 goto out;
 553                         }
 554
 555                         BUFFER_TRACE(gdb, "get_write_access");
 556                         err = ext4_journal_get_write_access(handle, gdb);
 557                         if (err) {
 558                                 brelse(gdb);
 559                                 goto out;
 560                         }
 561                         memcpy(gdb->b_data, sbi->s_group_desc[j]->b_data,
 562                                gdb->b_size);
 563                         set_buffer_uptodate(gdb);
 564
 565                         err = ext4_handle_dirty_metadata(handle, NULL, gdb);
 566                         if (unlikely(err)) {
 567                                 brelse(gdb);
 568                                 goto out;
 569                         }
 570                         brelse(gdb);
 571                 }
 572
 573                 /* Zero out all of the reserved backup group descriptor
 574                  * table blocks
 575                  */
 576                 if (ext4_bg_has_super(sb, group)) {
 577                         err = sb_issue_zeroout(sb, gdblocks + start + 1,
 578                                         reserved_gdb, GFP_NOFS);
 579                         if (err)
 580                                 goto out;
 581                 }
 582
 583 handle_itb:
 584                 /* Initialize group tables of the grop @group */
 585                 if (!(bg_flags[i] & EXT4_BG_INODE_ZEROED))
 586                         goto handle_bb;
 587
 588                 /* Zero out all of the inode table blocks */
 589                 block = group_data[i].inode_table;
 590                 ext4_debug("clear inode table blocks %#04llx -> %#04lx\n",
 591                            block, sbi->s_itb_per_group);
 592                 err = sb_issue_zeroout(sb, block, sbi->s_itb_per_group,
 593                                        GFP_NOFS);
 594                 if (err)
 595                         goto out;
 596
 597 handle_bb:
 598                 if (bg_flags[i] & EXT4_BG_BLOCK_UNINIT)
 599                         goto handle_ib;
 600
 601                 /* Initialize block bitmap of the @group */
 602                 block = group_data[i].block_bitmap;
 603                 err = extend_or_restart_transaction(handle, 1);
 604                 if (err)
 605                         goto out;
 606
 607                 bh = bclean(handle, sb, block);
 608                 if (IS_ERR(bh)) {
 609                         err = PTR_ERR(bh);
 610                         goto out;
 611                 }
 612                 overhead = ext4_group_overhead_blocks(sb, group);
 613                 if (overhead != 0) {
 614                         ext4_debug("mark backup superblock %#04llx (+0)\n",
 615                                    start);
 616                         ext4_set_bits(bh->b_data, 0,
 617                                       EXT4_NUM_B2C(sbi, overhead));
 618                 }
 619                 ext4_mark_bitmap_end(EXT4_B2C(sbi, group_data[i].blocks_count),
 620                                      sb->s_blocksize * 8, bh->b_data);
 621                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
 622                 brelse(bh);
 623                 if (err)
 624                         goto out;
 625
 626 handle_ib:
 627                 if (bg_flags[i] & EXT4_BG_INODE_UNINIT)
 628                         continue;
 629
 630                 /* Initialize inode bitmap of the @group */
 631                 block = group_data[i].inode_bitmap;
 632                 err = extend_or_restart_transaction(handle, 1);
 633                 if (err)
 634                         goto out;
 635                 /* Mark unused entries in inode bitmap used */
 636                 bh = bclean(handle, sb, block);
 637                 if (IS_ERR(bh)) {
 638                         err = PTR_ERR(bh);
 639                         goto out;
 640                 }
 641
 642                 ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb),
 643                                      sb->s_blocksize * 8, bh->b_data);
 644                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
 645                 brelse(bh);
 646                 if (err)
 647                         goto out;
 648         }
 649
 650         /* Mark group tables in block bitmap */
 651         for (j = 0; j < GROUP_TABLE_COUNT; j++) {
 652                 count = group_table_count[j];
 653                 start = (&group_data[0].block_bitmap)[j];
 654                 block = start;
 655                 for (i = 1; i < flex_gd->count; i++) {
 656                         block += group_table_count[j];
 657                         if (block == (&group_data[i].block_bitmap)[j]) {
 658                                 count += group_table_count[j];
 659                                 continue;
 660                         }
 661                         err = set_flexbg_block_bitmap(sb, handle,
 662                                                       flex_gd,
 663                                                       EXT4_B2C(sbi, start),
 664                                                       EXT4_B2C(sbi,
 665                                                                start + count
 666                                                                - 1));
 667                         if (err)
 668                                 goto out;
 669                         count = group_table_count[j];
 670                         start = (&group_data[i].block_bitmap)[j];
 671                         block = start;
 672                 }
 673
 674                 if (count) {
 675                         err = set_flexbg_block_bitmap(sb, handle,
 676                                                       flex_gd,
 677                                                       EXT4_B2C(sbi, start),
 678                                                       EXT4_B2C(sbi,
 679                                                                start + count
 680                                                                - 1));
 681                         if (err)
 682                                 goto out;
 683                 }
 684         }
 685
 686 out:
 687         err2 = ext4_journal_stop(handle);
 688         if (err2 && !err)
 689                 err = err2;
 690
 691         return err;
 692 }
 693
 694 /*
 695  * Iterate through the groups which hold BACKUP superblock/GDT copies in an
 696  * ext4 filesystem.  The counters should be initialized to 1, 5, and 7 before
 697  * calling this for the first time.  In a sparse filesystem it will be the
 698  * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ...
 699  * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ...
 700  */
 701 static unsigned ext4_list_backups(struct super_block *sb, unsigned *three,
 702                                   unsigned *five, unsigned *seven)
 703 {
 704         unsigned *min = three;
 705         int mult = 3;
 706         unsigned ret;
 707
 708         if (!ext4_has_feature_sparse_super(sb)) {
 709                 ret = *min;
 710                 *min += 1;
 711                 return ret;
 712         }
 713
 714         if (*five < *min) {
 715                 min = five;
 716                 mult = 5;
 717         }
 718         if (*seven < *min) {
 719                 min = seven;
 720                 mult = 7;
 721         }
 722
 723         ret = *min;
 724         *min *= mult;
 725
 726         return ret;
 727 }
 728
 729 /*
 730  * Check that all of the backup GDT blocks are held in the primary GDT block.
 731  * It is assumed that they are stored in group order.  Returns the number of
 732  * groups in current filesystem that have BACKUPS, or -ve error code.
 733  */
 734 static int verify_reserved_gdb(struct super_block *sb,
 735                                ext4_group_t end,
 736                                struct buffer_head *primary)
 737 {
 738         const ext4_fsblk_t blk = primary->b_blocknr;
 739         unsigned three = 1;
 740         unsigned five = 5;
 741         unsigned seven = 7;
 742         unsigned grp;
 743         __le32 *p = (__le32 *)primary->b_data;
 744         int gdbackups = 0;
 745
 746         while ((grp = ext4_list_backups(sb, &three, &five, &seven)) < end) {
 747                 if (le32_to_cpu(*p++) !=
 748                     grp * EXT4_BLOCKS_PER_GROUP(sb) + blk){
 749                         ext4_warning(sb, "reserved GDT %llu"
 750                                      " missing grp %d (%llu)",
 751                                      blk, grp,
 752                                      grp *
 753                                      (ext4_fsblk_t)EXT4_BLOCKS_PER_GROUP(sb) +
 754                                      blk);
 755                         return -EINVAL;
 756                 }
 757                 if (++gdbackups > EXT4_ADDR_PER_BLOCK(sb))
 758                         return -EFBIG;
 759         }
 760
 761         return gdbackups;
 762 }
 763
 764 /*
 765  * Called when we need to bring a reserved group descriptor table block into
 766  * use from the resize inode.  The primary copy of the new GDT block currently
 767  * is an indirect block (under the double indirect block in the resize inode).
 768  * The new backup GDT blocks will be stored as leaf blocks in this indirect
 769  * block, in group order.  Even though we know all the block numbers we need,
 770  * we check to ensure that the resize inode has actually reserved these blocks.
 771  *
 772  * Don't need to update the block bitmaps because the blocks are still in use.
 773  *
 774  * We get all of the error cases out of the way, so that we are sure to not
 775  * fail once we start modifying the data on disk, because JBD has no rollback.
 776  */
 777 static int add_new_gdb(handle_t *handle, struct inode *inode,
 778                        ext4_group_t group)
 779 {
 780         struct super_block *sb = inode->i_sb;
 781         struct ext4_super_block *es = EXT4_SB(sb)->s_es;
 782         unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
 783         ext4_fsblk_t gdblock = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + gdb_num;
 784         struct buffer_head **o_group_desc, **n_group_desc;
 785         struct buffer_head *dind;
 786         struct buffer_head *gdb_bh;
 787         int gdbackups;
 788         struct ext4_iloc iloc;
 789         __le32 *data;
 790         int err;
 791
 792         if (test_opt(sb, DEBUG))
 793                 printk(KERN_DEBUG
 794                        "EXT4-fs: ext4_add_new_gdb: adding group block %lu\n",
 795                        gdb_num);
 796
 797         gdb_bh = sb_bread(sb, gdblock);
 798         if (!gdb_bh)
 799                 return -EIO;
 800
 801         gdbackups = verify_reserved_gdb(sb, group, gdb_bh);
 802         if (gdbackups < 0) {
 803                 err = gdbackups;
 804                 goto exit_bh;
 805         }
 806
 807         data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
 808         dind = sb_bread(sb, le32_to_cpu(*data));
 809         if (!dind) {
 810                 err = -EIO;
 811                 goto exit_bh;
 812         }
 813
 814         data = (__le32 *)dind->b_data;
 815         if (le32_to_cpu(data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)]) != gdblock) {
 816                 ext4_warning(sb, "new group %u GDT block %llu not reserved",
 817                              group, gdblock);
 818                 err = -EINVAL;
 819                 goto exit_dind;
 820         }
 821
 822         BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
 823         err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
 824         if (unlikely(err))
 825                 goto exit_dind;
 826
 827         BUFFER_TRACE(gdb_bh, "get_write_access");
 828         err = ext4_journal_get_write_access(handle, gdb_bh);
 829         if (unlikely(err))
 830                 goto exit_dind;
 831
 832         BUFFER_TRACE(dind, "get_write_access");
 833         err = ext4_journal_get_write_access(handle, dind);
 834         if (unlikely(err))
 835                 ext4_std_error(sb, err);
 836
 837         /* ext4_reserve_inode_write() gets a reference on the iloc */
 838         err = ext4_reserve_inode_write(handle, inode, &iloc);
 839         if (unlikely(err))
 840                 goto exit_dind;
 841
 842         n_group_desc = ext4_kvmalloc((gdb_num + 1) *
 843                                      sizeof(struct buffer_head *),
 844                                      GFP_NOFS);
 845         if (!n_group_desc) {
 846                 err = -ENOMEM;
 847                 ext4_warning(sb, "not enough memory for %lu groups",
 848                              gdb_num + 1);
 849                 goto exit_inode;
 850         }
 851
 852         /*
 853          * Finally, we have all of the possible failures behind us...
 854          *
 855          * Remove new GDT block from inode double-indirect block and clear out
 856          * the new GDT block for use (which also "frees" the backup GDT blocks
 857          * from the reserved inode).  We don't need to change the bitmaps for
 858          * these blocks, because they are marked as in-use from being in the
 859          * reserved inode, and will become GDT blocks (primary and backup).
 860          */
 861         data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)] = 0;
 862         err = ext4_handle_dirty_metadata(handle, NULL, dind);
 863         if (unlikely(err)) {
 864                 ext4_std_error(sb, err);
 865                 goto exit_inode;
 866         }
 867         inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >>
 868                            (9 - EXT4_SB(sb)->s_cluster_bits);
 869         ext4_mark_iloc_dirty(handle, inode, &iloc);
 870         memset(gdb_bh->b_data, 0, sb->s_blocksize);
 871         err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
 872         if (unlikely(err)) {
 873                 ext4_std_error(sb, err);
 874                 goto exit_inode;
 875         }
 876         brelse(dind);
 877
 878         o_group_desc = EXT4_SB(sb)->s_group_desc;
 879         memcpy(n_group_desc, o_group_desc,
 880                EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
 881         n_group_desc[gdb_num] = gdb_bh;
 882         EXT4_SB(sb)->s_group_desc = n_group_desc;
 883         EXT4_SB(sb)->s_gdb_count++;
 884         kvfree(o_group_desc);
 885
 886         le16_add_cpu(&es->s_reserved_gdt_blocks, -1);
 887         err = ext4_handle_dirty_super(handle, sb);
 888         if (err)
 889                 ext4_std_error(sb, err);
 890
 891         return err;
 892
 893 exit_inode:
 894         kvfree(n_group_desc);
 895         brelse(iloc.bh);
 896 exit_dind:
 897         brelse(dind);
 898 exit_bh:
 899         brelse(gdb_bh);
 900
 901         ext4_debug("leaving with error %d\n", err);
 902         return err;
 903 }
 904
 905 /*
 906  * add_new_gdb_meta_bg is the sister of add_new_gdb.
 907  */
 908 static int add_new_gdb_meta_bg(struct super_block *sb,
 909                                handle_t *handle, ext4_group_t group) {
 910         ext4_fsblk_t gdblock;
 911         struct buffer_head *gdb_bh;
 912         struct buffer_head **o_group_desc, **n_group_desc;
 913         unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
 914         int err;
 915
 916         gdblock = ext4_meta_bg_first_block_no(sb, group) +
 917                    ext4_bg_has_super(sb, group);
 918         gdb_bh = sb_bread(sb, gdblock);
 919         if (!gdb_bh)
 920                 return -EIO;
 921         n_group_desc = ext4_kvmalloc((gdb_num + 1) *
 922                                      sizeof(struct buffer_head *),
 923                                      GFP_NOFS);
 924         if (!n_group_desc) {
 925                 err = -ENOMEM;
 926                 ext4_warning(sb, "not enough memory for %lu groups",
 927                              gdb_num + 1);
 928                 return err;
 929         }
 930
 931         o_group_desc = EXT4_SB(sb)->s_group_desc;
 932         memcpy(n_group_desc, o_group_desc,
 933                EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
 934         n_group_desc[gdb_num] = gdb_bh;
 935         EXT4_SB(sb)->s_group_desc = n_group_desc;
 936         EXT4_SB(sb)->s_gdb_count++;
 937         kvfree(o_group_desc);
 938         BUFFER_TRACE(gdb_bh, "get_write_access");
 939         err = ext4_journal_get_write_access(handle, gdb_bh);
 940         if (unlikely(err))
 941                 brelse(gdb_bh);
 942         return err;
 943 }
 944
 945 /*
 946  * Called when we are adding a new group which has a backup copy of each of
 947  * the GDT blocks (i.e. sparse group) and there are reserved GDT blocks.
 948  * We need to add these reserved backup GDT blocks to the resize inode, so
 949  * that they are kept for future resizing and not allocated to files.
 950  *
 951  * Each reserved backup GDT block will go into a different indirect block.
 952  * The indirect blocks are actually the primary reserved GDT blocks,
 953  * so we know in advance what their block numbers are.  We only get the
 954  * double-indirect block to verify it is pointing to the primary reserved
 955  * GDT blocks so we don't overwrite a data block by accident.  The reserved
 956  * backup GDT blocks are stored in their reserved primary GDT block.
 957  */
 958 static int reserve_backup_gdb(handle_t *handle, struct inode *inode,
 959                               ext4_group_t group)
 960 {
 961         struct super_block *sb = inode->i_sb;
 962         int reserved_gdb =le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
 963         int cluster_bits = EXT4_SB(sb)->s_cluster_bits;
 964         struct buffer_head **primary;
 965         struct buffer_head *dind;
 966         struct ext4_iloc iloc;
 967         ext4_fsblk_t blk;
 968         __le32 *data, *end;
 969         int gdbackups = 0;
 970         int res, i;
 971         int err;
 972
 973         primary = kmalloc_array(reserved_gdb, sizeof(*primary), GFP_NOFS);
 974         if (!primary)
 975                 return -ENOMEM;
 976
 977         data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
 978         dind = sb_bread(sb, le32_to_cpu(*data));
 979         if (!dind) {
 980                 err = -EIO;
 981                 goto exit_free;
 982         }
 983
 984         blk = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + EXT4_SB(sb)->s_gdb_count;
 985         data = (__le32 *)dind->b_data + (EXT4_SB(sb)->s_gdb_count %
 986                                          EXT4_ADDR_PER_BLOCK(sb));
 987         end = (__le32 *)dind->b_data + EXT4_ADDR_PER_BLOCK(sb);
 988
 989         /* Get each reserved primary GDT block and verify it holds backups */
 990         for (res = 0; res < reserved_gdb; res++, blk++) {
 991                 if (le32_to_cpu(*data) != blk) {
 992                         ext4_warning(sb, "reserved block %llu"
 993                                      " not at offset %ld",
 994                                      blk,
 995                                      (long)(data - (__le32 *)dind->b_data));
 996                         err = -EINVAL;
 997                         goto exit_bh;
 998                 }
 999                 primary[res] = sb_bread(sb, blk);
1000                 if (!primary[res]) {
1001                         err = -EIO;
1002                         goto exit_bh;
1003                 }
1004                 gdbackups = verify_reserved_gdb(sb, group, primary[res]);
1005                 if (gdbackups < 0) {
1006                         brelse(primary[res]);
1007                         err = gdbackups;
1008                         goto exit_bh;
1009                 }
1010                 if (++data >= end)
1011                         data = (__le32 *)dind->b_data;
1012         }
1013
1014         for (i = 0; i < reserved_gdb; i++) {
1015                 BUFFER_TRACE(primary[i], "get_write_access");
1016                 if ((err = ext4_journal_get_write_access(handle, primary[i])))
1017                         goto exit_bh;
1018         }
1019
1020         if ((err = ext4_reserve_inode_write(handle, inode, &iloc)))
1021                 goto exit_bh;
1022
1023         /*
1024          * Finally we can add each of the reserved backup GDT blocks from
1025          * the new group to its reserved primary GDT block.
1026          */
1027         blk = group * EXT4_BLOCKS_PER_GROUP(sb);
1028         for (i = 0; i < reserved_gdb; i++) {
1029                 int err2;
1030                 data = (__le32 *)primary[i]->b_data;
1031                 /* printk("reserving backup %lu[%u] = %lu\n",
1032                        primary[i]->b_blocknr, gdbackups,
1033                        blk + primary[i]->b_blocknr); */
1034                 data[gdbackups] = cpu_to_le32(blk + primary[i]->b_blocknr);
1035                 err2 = ext4_handle_dirty_metadata(handle, NULL, primary[i]);
1036                 if (!err)
1037                         err = err2;
1038         }
1039
1040         inode->i_blocks += reserved_gdb * sb->s_blocksize >> (9 - cluster_bits);
1041         ext4_mark_iloc_dirty(handle, inode, &iloc);
1042
1043 exit_bh:
1044         while (--res >= 0)
1045                 brelse(primary[res]);
1046         brelse(dind);
1047
1048 exit_free:
1049         kfree(primary);
1050
1051         return err;
1052 }
1053
1054 /*
1055  * Update the backup copies of the ext4 metadata.  These don't need to be part
1056  * of the main resize transaction, because e2fsck will re-write them if there
1057  * is a problem (basically only OOM will cause a problem).  However, we
1058  * _should_ update the backups if possible, in case the primary gets trashed
1059  * for some reason and we need to run e2fsck from a backup superblock.  The
1060  * important part is that the new block and inode counts are in the backup
1061  * superblocks, and the location of the new group metadata in the GDT backups.
1062  *
1063  * We do not need take the s_resize_lock for this, because these
1064  * blocks are not otherwise touched by the filesystem code when it is
1065  * mounted.  We don't need to worry about last changing from
1066  * sbi->s_groups_count, because the worst that can happen is that we
1067  * do not copy the full number of backups at this time.  The resize
1068  * which changed s_groups_count will backup again.
1069  */
1070 static void update_backups(struct super_block *sb, sector_t blk_off, char *data,
1071                            int size, int meta_bg)
1072 {
1073         struct ext4_sb_info *sbi = EXT4_SB(sb);
1074         ext4_group_t last;
1075         const int bpg = EXT4_BLOCKS_PER_GROUP(sb);
1076         unsigned three = 1;
1077         unsigned five = 5;
1078         unsigned seven = 7;
1079         ext4_group_t group = 0;
1080         int rest = sb->s_blocksize - size;
1081         handle_t *handle;
1082         int err = 0, err2;
1083
1084         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, EXT4_MAX_TRANS_DATA);
1085         if (IS_ERR(handle)) {
1086                 group = 1;
1087                 err = PTR_ERR(handle);
1088                 goto exit_err;
1089         }
1090
1091         if (meta_bg == 0) {
1092                 group = ext4_list_backups(sb, &three, &five, &seven);
1093                 last = sbi->s_groups_count;
1094         } else {
1095                 group = ext4_get_group_number(sb, blk_off) + 1;
1096                 last = (ext4_group_t)(group + EXT4_DESC_PER_BLOCK(sb) - 2);
1097         }
1098
1099         while (group < sbi->s_groups_count) {
1100                 struct buffer_head *bh;
1101                 ext4_fsblk_t backup_block;
1102
1103                 /* Out of journal space, and can't get more - abort - so sad */
1104                 if (ext4_handle_valid(handle) &&
1105                     handle->h_buffer_credits == 0 &&
1106                     ext4_journal_extend(handle, EXT4_MAX_TRANS_DATA) &&
1107                     (err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA)))
1108                         break;
1109
1110                 if (meta_bg == 0)
1111                         backup_block = ((ext4_fsblk_t)group) * bpg + blk_off;
1112                 else
1113                         backup_block = (ext4_group_first_block_no(sb, group) +
1114                                         ext4_bg_has_super(sb, group));
1115
1116                 bh = sb_getblk(sb, backup_block);
1117                 if (unlikely(!bh)) {
1118                         err = -ENOMEM;
1119                         break;
1120                 }
1121                 ext4_debug("update metadata backup %llu(+%llu)\n",
1122                            backup_block, backup_block -
1123                            ext4_group_first_block_no(sb, group));
1124                 BUFFER_TRACE(bh, "get_write_access");
1125                 if ((err = ext4_journal_get_write_access(handle, bh)))
1126                         break;
1127                 lock_buffer(bh);
1128                 memcpy(bh->b_data, data, size);
1129                 if (rest)
1130                         memset(bh->b_data + size, 0, rest);
1131                 set_buffer_uptodate(bh);
1132                 unlock_buffer(bh);
1133                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
1134                 if (unlikely(err))
1135                         ext4_std_error(sb, err);
1136                 brelse(bh);
1137
1138                 if (meta_bg == 0)
1139                         group = ext4_list_backups(sb, &three, &five, &seven);
1140                 else if (group == last)
1141                         break;
1142                 else
1143                         group = last;
1144         }
1145         if ((err2 = ext4_journal_stop(handle)) && !err)
1146                 err = err2;
1147
1148         /*
1149          * Ugh! Need to have e2fsck write the backup copies.  It is too
1150          * late to revert the resize, we shouldn't fail just because of
1151          * the backup copies (they are only needed in case of corruption).
1152          *
1153          * However, if we got here we have a journal problem too, so we
1154          * can't really start a transaction to mark the superblock.
1155          * Chicken out and just set the flag on the hope it will be written
1156          * to disk, and if not - we will simply wait until next fsck.
1157          */
1158 exit_err:
1159         if (err) {
1160                 ext4_warning(sb, "can't update backup for group %u (err %d), "
1161                              "forcing fsck on next reboot", group, err);
1162                 sbi->s_mount_state &= ~EXT4_VALID_FS;
1163                 sbi->s_es->s_state &= cpu_to_le16(~EXT4_VALID_FS);
1164                 mark_buffer_dirty(sbi->s_sbh);
1165         }
1166 }
1167
1168 /*
1169  * ext4_add_new_descs() adds @count group descriptor of groups
1170  * starting at @group
1171  *
1172  * @handle: journal handle
1173  * @sb: super block
1174  * @group: the group no. of the first group desc to be added
1175  * @resize_inode: the resize inode
1176  * @count: number of group descriptors to be added
1177  */
1178 static int ext4_add_new_descs(handle_t *handle, struct super_block *sb,
1179                               ext4_group_t group, struct inode *resize_inode,
1180                               ext4_group_t count)
1181 {
1182         struct ext4_sb_info *sbi = EXT4_SB(sb);
1183         struct ext4_super_block *es = sbi->s_es;
1184         struct buffer_head *gdb_bh;
1185         int i, gdb_off, gdb_num, err = 0;
1186         int meta_bg;
1187
1188         meta_bg = ext4_has_feature_meta_bg(sb);
1189         for (i = 0; i < count; i++, group++) {
1190                 int reserved_gdb = ext4_bg_has_super(sb, group) ?
1191                         le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1192
1193                 gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1194                 gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1195
1196                 /*
1197                  * We will only either add reserved group blocks to a backup group
1198                  * or remove reserved blocks for the first group in a new group block.
1199                  * Doing both would be mean more complex code, and sane people don't
1200                  * use non-sparse filesystems anymore.  This is already checked above.
1201                  */
1202                 if (gdb_off) {
1203                         gdb_bh = sbi->s_group_desc[gdb_num];
1204                         BUFFER_TRACE(gdb_bh, "get_write_access");
1205                         err = ext4_journal_get_write_access(handle, gdb_bh);
1206
1207                         if (!err && reserved_gdb && ext4_bg_num_gdb(sb, group))
1208                                 err = reserve_backup_gdb(handle, resize_inode, group);
1209                 } else if (meta_bg != 0) {
1210                         err = add_new_gdb_meta_bg(sb, handle, group);
1211                 } else {
1212                         err = add_new_gdb(handle, resize_inode, group);
1213                 }
1214                 if (err)
1215                         break;
1216         }
1217         return err;
1218 }
1219
1220 static struct buffer_head *ext4_get_bitmap(struct super_block *sb, __u64 block)
1221 {
1222         struct buffer_head *bh = sb_getblk(sb, block);
1223         if (unlikely(!bh))
1224                 return NULL;
1225         if (!bh_uptodate_or_lock(bh)) {
1226                 if (bh_submit_read(bh) < 0) {
1227                         brelse(bh);
1228                         return NULL;
1229                 }
1230         }
1231
1232         return bh;
1233 }
1234
1235 static int ext4_set_bitmap_checksums(struct super_block *sb,
1236                                      ext4_group_t group,
1237                                      struct ext4_group_desc *gdp,
1238                                      struct ext4_new_group_data *group_data)
1239 {
1240         struct buffer_head *bh;
1241
1242         if (!ext4_has_metadata_csum(sb))
1243                 return 0;
1244
1245         bh = ext4_get_bitmap(sb, group_data->inode_bitmap);
1246         if (!bh)
1247                 return -EIO;
1248         ext4_inode_bitmap_csum_set(sb, group, gdp, bh,
1249                                    EXT4_INODES_PER_GROUP(sb) / 8);
1250         brelse(bh);
1251
1252         bh = ext4_get_bitmap(sb, group_data->block_bitmap);
1253         if (!bh)
1254                 return -EIO;
1255         ext4_block_bitmap_csum_set(sb, group, gdp, bh);
1256         brelse(bh);
1257
1258         return 0;
1259 }
1260
1261 /*
1262  * ext4_setup_new_descs() will set up the group descriptor descriptors of a flex bg
1263  */
1264 static int ext4_setup_new_descs(handle_t *handle, struct super_block *sb,
1265                                 struct ext4_new_flex_group_data *flex_gd)
1266 {
1267         struct ext4_new_group_data      *group_data = flex_gd->groups;
1268         struct ext4_group_desc          *gdp;
1269         struct ext4_sb_info             *sbi = EXT4_SB(sb);
1270         struct buffer_head              *gdb_bh;
1271         ext4_group_t                    group;
1272         __u16                           *bg_flags = flex_gd->bg_flags;
1273         int                             i, gdb_off, gdb_num, err = 0;
1274
1275
1276         for (i = 0; i < flex_gd->count; i++, group_data++, bg_flags++) {
1277                 group = group_data->group;
1278
1279                 gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1280                 gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1281
1282                 /*
1283                  * get_write_access() has been called on gdb_bh by ext4_add_new_desc().
1284                  */
1285                 gdb_bh = sbi->s_group_desc[gdb_num];
1286                 /* Update group descriptor block for new group */
1287                 gdp = (struct ext4_group_desc *)(gdb_bh->b_data +
1288                                                  gdb_off * EXT4_DESC_SIZE(sb));
1289
1290                 memset(gdp, 0, EXT4_DESC_SIZE(sb));
1291                 ext4_block_bitmap_set(sb, gdp, group_data->block_bitmap);
1292                 ext4_inode_bitmap_set(sb, gdp, group_data->inode_bitmap);
1293                 err = ext4_set_bitmap_checksums(sb, group, gdp, group_data);
1294                 if (err) {
1295                         ext4_std_error(sb, err);
1296                         break;
1297                 }
1298
1299                 ext4_inode_table_set(sb, gdp, group_data->inode_table);
1300                 ext4_free_group_clusters_set(sb, gdp,
1301                                              group_data->free_clusters_count);
1302                 ext4_free_inodes_set(sb, gdp, EXT4_INODES_PER_GROUP(sb));
1303                 if (ext4_has_group_desc_csum(sb))
1304                         ext4_itable_unused_set(sb, gdp,
1305                                                EXT4_INODES_PER_GROUP(sb));
1306                 gdp->bg_flags = cpu_to_le16(*bg_flags);
1307                 ext4_group_desc_csum_set(sb, group, gdp);
1308
1309                 err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
1310                 if (unlikely(err)) {
1311                         ext4_std_error(sb, err);
1312                         break;
1313                 }
1314
1315                 /*
1316                  * We can allocate memory for mb_alloc based on the new group
1317                  * descriptor
1318                  */
1319                 err = ext4_mb_add_groupinfo(sb, group, gdp);
1320                 if (err)
1321                         break;
1322         }
1323         return err;
1324 }
1325
1326 /*
1327  * ext4_update_super() updates the super block so that the newly added
1328  * groups can be seen by the filesystem.
1329  *
1330  * @sb: super block
1331  * @flex_gd: new added groups
1332  */
1333 static void ext4_update_super(struct super_block *sb,
1334                              struct ext4_new_flex_group_data *flex_gd)
1335 {
1336         ext4_fsblk_t blocks_count = 0;
1337         ext4_fsblk_t free_blocks = 0;
1338         ext4_fsblk_t reserved_blocks = 0;
1339         struct ext4_new_group_data *group_data = flex_gd->groups;
1340         struct ext4_sb_info *sbi = EXT4_SB(sb);
1341         struct ext4_super_block *es = sbi->s_es;
1342         int i;
1343
1344         BUG_ON(flex_gd->count == 0 || group_data == NULL);
1345         /*
1346          * Make the new blocks and inodes valid next.  We do this before
1347          * increasing the group count so that once the group is enabled,
1348          * all of its blocks and inodes are already valid.
1349          *
1350          * We always allocate group-by-group, then block-by-block or
1351          * inode-by-inode within a group, so enabling these
1352          * blocks/inodes before the group is live won't actually let us
1353          * allocate the new space yet.
1354          */
1355         for (i = 0; i < flex_gd->count; i++) {
1356                 blocks_count += group_data[i].blocks_count;
1357                 free_blocks += EXT4_C2B(sbi, group_data[i].free_clusters_count);
1358         }
1359
1360         reserved_blocks = ext4_r_blocks_count(es) * 100;
1361         reserved_blocks = div64_u64(reserved_blocks, ext4_blocks_count(es));
1362         reserved_blocks *= blocks_count;
1363         do_div(reserved_blocks, 100);
1364
1365         ext4_blocks_count_set(es, ext4_blocks_count(es) + blocks_count);
1366         ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + free_blocks);
1367         le32_add_cpu(&es->s_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1368                      flex_gd->count);
1369         le32_add_cpu(&es->s_free_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1370                      flex_gd->count);
1371
1372         ext4_debug("free blocks count %llu", ext4_free_blocks_count(es));
1373         /*
1374          * We need to protect s_groups_count against other CPUs seeing
1375          * inconsistent state in the superblock.
1376          *
1377          * The precise rules we use are:
1378          *
1379          * * Writers must perform a smp_wmb() after updating all
1380          *   dependent data and before modifying the groups count
1381          *
1382          * * Readers must perform an smp_rmb() after reading the groups
1383          *   count and before reading any dependent data.
1384          *
1385          * NB. These rules can be relaxed when checking the group count
1386          * while freeing data, as we can only allocate from a block
1387          * group after serialising against the group count, and we can
1388          * only then free after serialising in turn against that
1389          * allocation.
1390          */
1391         smp_wmb();
1392
1393         /* Update the global fs size fields */
1394         sbi->s_groups_count += flex_gd->count;
1395         sbi->s_blockfile_groups = min_t(ext4_group_t, sbi->s_groups_count,
1396                         (EXT4_MAX_BLOCK_FILE_PHYS / EXT4_BLOCKS_PER_GROUP(sb)));
1397
1398         /* Update the reserved block counts only once the new group is
1399          * active. */
1400         ext4_r_blocks_count_set(es, ext4_r_blocks_count(es) +
1401                                 reserved_blocks);
1402
1403         /* Update the free space counts */
1404         percpu_counter_add(&sbi->s_freeclusters_counter,
1405                            EXT4_NUM_B2C(sbi, free_blocks));
1406         percpu_counter_add(&sbi->s_freeinodes_counter,
1407                            EXT4_INODES_PER_GROUP(sb) * flex_gd->count);
1408
1409         ext4_debug("free blocks count %llu",
1410                    percpu_counter_read(&sbi->s_freeclusters_counter));
1411         if (ext4_has_feature_flex_bg(sb) && sbi->s_log_groups_per_flex) {
1412                 ext4_group_t flex_group;
1413                 flex_group = ext4_flex_group(sbi, group_data[0].group);
1414                 atomic64_add(EXT4_NUM_B2C(sbi, free_blocks),
1415                              &sbi->s_flex_groups[flex_group].free_clusters);
1416                 atomic_add(EXT4_INODES_PER_GROUP(sb) * flex_gd->count,
1417                            &sbi->s_flex_groups[flex_group].free_inodes);
1418         }
1419
1420         /*
1421          * Update the fs overhead information
1422          */
1423         ext4_calculate_overhead(sb);
1424
1425         if (test_opt(sb, DEBUG))
1426                 printk(KERN_DEBUG "EXT4-fs: added group %u:"
1427                        "%llu blocks(%llu free %llu reserved)\n", flex_gd->count,
1428                        blocks_count, free_blocks, reserved_blocks);
1429 }
1430
1431 /* Add a flex group to an fs. Ensure we handle all possible error conditions
1432  * _before_ we start modifying the filesystem, because we cannot abort the
1433  * transaction and not have it write the data to disk.
1434  */
1435 static int ext4_flex_group_add(struct super_block *sb,
1436                                struct inode *resize_inode,
1437                                struct ext4_new_flex_group_data *flex_gd)
1438 {
1439         struct ext4_sb_info *sbi = EXT4_SB(sb);
1440         struct ext4_super_block *es = sbi->s_es;
1441         ext4_fsblk_t o_blocks_count;
1442         ext4_grpblk_t last;
1443         ext4_group_t group;
1444         handle_t *handle;
1445         unsigned reserved_gdb;
1446         int err = 0, err2 = 0, credit;
1447
1448         BUG_ON(!flex_gd->count || !flex_gd->groups || !flex_gd->bg_flags);
1449
1450         reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
1451         o_blocks_count = ext4_blocks_count(es);
1452         ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1453         BUG_ON(last);
1454
1455         err = setup_new_flex_group_blocks(sb, flex_gd);
1456         if (err)
1457                 goto exit;
1458         /*
1459          * We will always be modifying at least the superblock and  GDT
1460          * blocks.  If we are adding a group past the last current GDT block,
1461          * we will also modify the inode and the dindirect block.  If we
1462          * are adding a group with superblock/GDT backups  we will also
1463          * modify each of the reserved GDT dindirect blocks.
1464          */
1465         credit = 3;     /* sb, resize inode, resize inode dindirect */
1466         /* GDT blocks */
1467         credit += 1 + DIV_ROUND_UP(flex_gd->count, EXT4_DESC_PER_BLOCK(sb));
1468         credit += reserved_gdb; /* Reserved GDT dindirect blocks */
1469         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, credit);
1470         if (IS_ERR(handle)) {
1471                 err = PTR_ERR(handle);
1472                 goto exit;
1473         }
1474
1475         BUFFER_TRACE(sbi->s_sbh, "get_write_access");
1476         err = ext4_journal_get_write_access(handle, sbi->s_sbh);
1477         if (err)
1478                 goto exit_journal;
1479
1480         group = flex_gd->groups[0].group;
1481         BUG_ON(group != sbi->s_groups_count);
1482         err = ext4_add_new_descs(handle, sb, group,
1483                                 resize_inode, flex_gd->count);
1484         if (err)
1485                 goto exit_journal;
1486
1487         err = ext4_setup_new_descs(handle, sb, flex_gd);
1488         if (err)
1489                 goto exit_journal;
1490
1491         ext4_update_super(sb, flex_gd);
1492
1493         err = ext4_handle_dirty_super(handle, sb);
1494
1495 exit_journal:
1496         err2 = ext4_journal_stop(handle);
1497         if (!err)
1498                 err = err2;
1499
1500         if (!err) {
1501                 int gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1502                 int gdb_num_end = ((group + flex_gd->count - 1) /
1503                                    EXT4_DESC_PER_BLOCK(sb));
1504                 int meta_bg = ext4_has_feature_meta_bg(sb);
1505                 sector_t old_gdb = 0;
1506
1507                 update_backups(sb, sbi->s_sbh->b_blocknr, (char *)es,
1508                                sizeof(struct ext4_super_block), 0);
1509                 for (; gdb_num <= gdb_num_end; gdb_num++) {
1510                         struct buffer_head *gdb_bh;
1511
1512                         gdb_bh = sbi->s_group_desc[gdb_num];
1513                         if (old_gdb == gdb_bh->b_blocknr)
1514                                 continue;
1515                         update_backups(sb, gdb_bh->b_blocknr, gdb_bh->b_data,
1516                                        gdb_bh->b_size, meta_bg);
1517                         old_gdb = gdb_bh->b_blocknr;
1518                 }
1519         }
1520 exit:
1521         return err;
1522 }
1523
1524 static int ext4_setup_next_flex_gd(struct super_block *sb,
1525                                     struct ext4_new_flex_group_data *flex_gd,
1526                                     ext4_fsblk_t n_blocks_count,
1527                                     unsigned long flexbg_size)
1528 {
1529         struct ext4_sb_info *sbi = EXT4_SB(sb);
1530         struct ext4_super_block *es = sbi->s_es;
1531         struct ext4_new_group_data *group_data = flex_gd->groups;
1532         ext4_fsblk_t o_blocks_count;
1533         ext4_group_t n_group;
1534         ext4_group_t group;
1535         ext4_group_t last_group;
1536         ext4_grpblk_t last;
1537         ext4_grpblk_t clusters_per_group;
1538         unsigned long i;
1539
1540         clusters_per_group = EXT4_CLUSTERS_PER_GROUP(sb);
1541
1542         o_blocks_count = ext4_blocks_count(es);
1543
1544         if (o_blocks_count == n_blocks_count)
1545                 return 0;
1546
1547         ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1548         BUG_ON(last);
1549         ext4_get_group_no_and_offset(sb, n_blocks_count - 1, &n_group, &last);
1550
1551         last_group = group | (flexbg_size - 1);
1552         if (last_group > n_group)
1553                 last_group = n_group;
1554
1555         flex_gd->count = last_group - group + 1;
1556
1557         for (i = 0; i < flex_gd->count; i++) {
1558                 int overhead;
1559
1560                 group_data[i].group = group + i;
1561                 group_data[i].blocks_count = EXT4_BLOCKS_PER_GROUP(sb);
1562                 overhead = ext4_group_overhead_blocks(sb, group + i);
1563                 group_data[i].mdata_blocks = overhead;
1564                 group_data[i].free_clusters_count = EXT4_CLUSTERS_PER_GROUP(sb);
1565                 if (ext4_has_group_desc_csum(sb)) {
1566                         flex_gd->bg_flags[i] = EXT4_BG_BLOCK_UNINIT |
1567                                                EXT4_BG_INODE_UNINIT;
1568                         if (!test_opt(sb, INIT_INODE_TABLE))
1569                                 flex_gd->bg_flags[i] |= EXT4_BG_INODE_ZEROED;
1570                 } else
1571                         flex_gd->bg_flags[i] = EXT4_BG_INODE_ZEROED;
1572         }
1573
1574         if (last_group == n_group && ext4_has_group_desc_csum(sb))
1575                 /* We need to initialize block bitmap of last group. */
1576                 flex_gd->bg_flags[i - 1] &= ~EXT4_BG_BLOCK_UNINIT;
1577
1578         if ((last_group == n_group) && (last != clusters_per_group - 1)) {
1579                 group_data[i - 1].blocks_count = EXT4_C2B(sbi, last + 1);
1580                 group_data[i - 1].free_clusters_count -= clusters_per_group -
1581                                                        last - 1;
1582         }
1583
1584         return 1;
1585 }
1586
1587 /* Add group descriptor data to an existing or new group descriptor block.
1588  * Ensure we handle all possible error conditions _before_ we start modifying
1589  * the filesystem, because we cannot abort the transaction and not have it
1590  * write the data to disk.
1591  *
1592  * If we are on a GDT block boundary, we need to get the reserved GDT block.
1593  * Otherwise, we may need to add backup GDT blocks for a sparse group.
1594  *
1595  * We only need to hold the superblock lock while we are actually adding
1596  * in the new group's counts to the superblock.  Prior to that we have
1597  * not really "added" the group at all.  We re-check that we are still
1598  * adding in the last group in case things have changed since verifying.
1599  */
1600 int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input)
1601 {
1602         struct ext4_new_flex_group_data flex_gd;
1603         struct ext4_sb_info *sbi = EXT4_SB(sb);
1604         struct ext4_super_block *es = sbi->s_es;
1605         int reserved_gdb = ext4_bg_has_super(sb, input->group) ?
1606                 le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1607         struct inode *inode = NULL;
1608         int gdb_off;
1609         int err;
1610         __u16 bg_flags = 0;
1611
1612         gdb_off = input->group % EXT4_DESC_PER_BLOCK(sb);
1613
1614         if (gdb_off == 0 && !ext4_has_feature_sparse_super(sb)) {
1615                 ext4_warning(sb, "Can't resize non-sparse filesystem further");
1616                 return -EPERM;
1617         }
1618
1619         if (ext4_blocks_count(es) + input->blocks_count <
1620             ext4_blocks_count(es)) {
1621                 ext4_warning(sb, "blocks_count overflow");
1622                 return -EINVAL;
1623         }
1624
1625         if (le32_to_cpu(es->s_inodes_count) + EXT4_INODES_PER_GROUP(sb) <
1626             le32_to_cpu(es->s_inodes_count)) {
1627                 ext4_warning(sb, "inodes_count overflow");
1628                 return -EINVAL;
1629         }
1630
1631         if (reserved_gdb || gdb_off == 0) {
1632                 if (ext4_has_feature_resize_inode(sb) ||
1633                     !le16_to_cpu(es->s_reserved_gdt_blocks)) {
1634                         ext4_warning(sb,
1635                                      "No reserved GDT blocks, can't resize");
1636                         return -EPERM;
1637                 }
1638                 inode = ext4_iget(sb, EXT4_RESIZE_INO);
1639                 if (IS_ERR(inode)) {
1640                         ext4_warning(sb, "Error opening resize inode");
1641                         return PTR_ERR(inode);
1642                 }
1643         }
1644
1645
1646         err = verify_group_input(sb, input);
1647         if (err)
1648                 goto out;
1649
1650         err = ext4_alloc_flex_bg_array(sb, input->group + 1);
1651         if (err)
1652                 goto out;
1653
1654         err = ext4_mb_alloc_groupinfo(sb, input->group + 1);
1655         if (err)
1656                 goto out;
1657
1658         flex_gd.count = 1;
1659         flex_gd.groups = input;
1660         flex_gd.bg_flags = &bg_flags;
1661         err = ext4_flex_group_add(sb, inode, &flex_gd);
1662 out:
1663         iput(inode);
1664         return err;
1665 } /* ext4_group_add */
1666
1667 /*
1668  * extend a group without checking assuming that checking has been done.
1669  */
1670 static int ext4_group_extend_no_check(struct super_block *sb,
1671                                       ext4_fsblk_t o_blocks_count, ext4_grpblk_t add)
1672 {
1673         struct ext4_super_block *es = EXT4_SB(sb)->s_es;
1674         handle_t *handle;
1675         int err = 0, err2;
1676
1677         /* We will update the superblock, one block bitmap, and
1678          * one group descriptor via ext4_group_add_blocks().
1679          */
1680         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, 3);
1681         if (IS_ERR(handle)) {
1682                 err = PTR_ERR(handle);
1683                 ext4_warning(sb, "error %d on journal start", err);
1684                 return err;
1685         }
1686
1687         BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
1688         err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
1689         if (err) {
1690                 ext4_warning(sb, "error %d on journal write access", err);
1691                 goto errout;
1692         }
1693
1694         ext4_blocks_count_set(es, o_blocks_count + add);
1695         ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + add);
1696         ext4_debug("freeing blocks %llu through %llu\n", o_blocks_count,
1697                    o_blocks_count + add);
1698         /* We add the blocks to the bitmap and set the group need init bit */
1699         err = ext4_group_add_blocks(handle, sb, o_blocks_count, add);
1700         if (err)
1701                 goto errout;
1702         ext4_handle_dirty_super(handle, sb);
1703         ext4_debug("freed blocks %llu through %llu\n", o_blocks_count,
1704                    o_blocks_count + add);
1705 errout:
1706         err2 = ext4_journal_stop(handle);
1707         if (err2 && !err)
1708                 err = err2;
1709
1710         if (!err) {
1711                 if (test_opt(sb, DEBUG))
1712                         printk(KERN_DEBUG "EXT4-fs: extended group to %llu "
1713                                "blocks\n", ext4_blocks_count(es));
1714                 update_backups(sb, EXT4_SB(sb)->s_sbh->b_blocknr,
1715                                (char *)es, sizeof(struct ext4_super_block), 0);
1716         }
1717         return err;
1718 }
1719
1720 /*
1721  * Extend the filesystem to the new number of blocks specified.  This entry
1722  * point is only used to extend the current filesystem to the end of the last
1723  * existing group.  It can be accessed via ioctl, or by "remount,resize=<size>"
1724  * for emergencies (because it has no dependencies on reserved blocks).
1725  *
1726  * If we _really_ wanted, we could use default values to call ext4_group_add()
1727  * allow the "remount" trick to work for arbitrary resizing, assuming enough
1728  * GDT blocks are reserved to grow to the desired size.
1729  */
1730 int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es,
1731                       ext4_fsblk_t n_blocks_count)
1732 {
1733         ext4_fsblk_t o_blocks_count;
1734         ext4_grpblk_t last;
1735         ext4_grpblk_t add;
1736         struct buffer_head *bh;
1737         int err;
1738         ext4_group_t group;
1739
1740         o_blocks_count = ext4_blocks_count(es);
1741
1742         if (test_opt(sb, DEBUG))
1743                 ext4_msg(sb, KERN_DEBUG,
1744                          "extending last group from %llu to %llu blocks",
1745                          o_blocks_count, n_blocks_count);
1746
1747         if (n_blocks_count == 0 || n_blocks_count == o_blocks_count)
1748                 return 0;
1749
1750         if (n_blocks_count > (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
1751                 ext4_msg(sb, KERN_ERR,
1752                          "filesystem too large to resize to %llu blocks safely",
1753                          n_blocks_count);
1754                 if (sizeof(sector_t) < 8)
1755                         ext4_warning(sb, "CONFIG_LBDAF not enabled");
1756                 return -EINVAL;
1757         }
1758
1759         if (n_blocks_count < o_blocks_count) {
1760                 ext4_warning(sb, "can't shrink FS - resize aborted");
1761                 return -EINVAL;
1762         }
1763
1764         /* Handle the remaining blocks in the last group only. */
1765         ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1766
1767         if (last == 0) {
1768                 ext4_warning(sb, "need to use ext2online to resize further");
1769                 return -EPERM;
1770         }
1771
1772         add = EXT4_BLOCKS_PER_GROUP(sb) - last;
1773
1774         if (o_blocks_count + add < o_blocks_count) {
1775                 ext4_warning(sb, "blocks_count overflow");
1776                 return -EINVAL;
1777         }
1778
1779         if (o_blocks_count + add > n_blocks_count)
1780                 add = n_blocks_count - o_blocks_count;
1781
1782         if (o_blocks_count + add < n_blocks_count)
1783                 ext4_warning(sb, "will only finish group (%llu blocks, %u new)",
1784                              o_blocks_count + add, add);
1785
1786         /* See if the device is actually as big as what was requested */
1787         bh = sb_bread(sb, o_blocks_count + add - 1);
1788         if (!bh) {
1789                 ext4_warning(sb, "can't read last block, resize aborted");
1790                 return -ENOSPC;
1791         }
1792         brelse(bh);
1793
1794         err = ext4_group_extend_no_check(sb, o_blocks_count, add);
1795         return err;
1796 } /* ext4_group_extend */
1797
1798
1799 static int num_desc_blocks(struct super_block *sb, ext4_group_t groups)
1800 {
1801         return (groups + EXT4_DESC_PER_BLOCK(sb) - 1) / EXT4_DESC_PER_BLOCK(sb);
1802 }
1803
1804 /*
1805  * Release the resize inode and drop the resize_inode feature if there
1806  * are no more reserved gdt blocks, and then convert the file system
1807  * to enable meta_bg
1808  */
1809 static int ext4_convert_meta_bg(struct super_block *sb, struct inode *inode)
1810 {
1811         handle_t *handle;
1812         struct ext4_sb_info *sbi = EXT4_SB(sb);
1813         struct ext4_super_block *es = sbi->s_es;
1814         struct ext4_inode_info *ei = EXT4_I(inode);
1815         ext4_fsblk_t nr;
1816         int i, ret, err = 0;
1817         int credits = 1;
1818
1819         ext4_msg(sb, KERN_INFO, "Converting file system to meta_bg");
1820         if (inode) {
1821                 if (es->s_reserved_gdt_blocks) {
1822                         ext4_error(sb, "Unexpected non-zero "
1823                                    "s_reserved_gdt_blocks");
1824                         return -EPERM;
1825                 }
1826
1827                 /* Do a quick sanity check of the resize inode */
1828                 if (inode->i_blocks != 1 << (inode->i_blkbits -
1829                                              (9 - sbi->s_cluster_bits)))
1830                         goto invalid_resize_inode;
1831                 for (i = 0; i < EXT4_N_BLOCKS; i++) {
1832                         if (i == EXT4_DIND_BLOCK) {
1833                                 if (ei->i_data[i])
1834                                         continue;
1835                                 else
1836                                         goto invalid_resize_inode;
1837                         }
1838                         if (ei->i_data[i])
1839                                 goto invalid_resize_inode;
1840                 }
1841                 credits += 3;   /* block bitmap, bg descriptor, resize inode */
1842         }
1843
1844         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, credits);
1845         if (IS_ERR(handle))
1846                 return PTR_ERR(handle);
1847
1848         BUFFER_TRACE(sbi->s_sbh, "get_write_access");
1849         err = ext4_journal_get_write_access(handle, sbi->s_sbh);
1850         if (err)
1851                 goto errout;
1852
1853         ext4_clear_feature_resize_inode(sb);
1854         ext4_set_feature_meta_bg(sb);
1855         sbi->s_es->s_first_meta_bg =
1856                 cpu_to_le32(num_desc_blocks(sb, sbi->s_groups_count));
1857
1858         err = ext4_handle_dirty_super(handle, sb);
1859         if (err) {
1860                 ext4_std_error(sb, err);
1861                 goto errout;
1862         }
1863
1864         if (inode) {
1865                 nr = le32_to_cpu(ei->i_data[EXT4_DIND_BLOCK]);
1866                 ext4_free_blocks(handle, inode, NULL, nr, 1,
1867                                  EXT4_FREE_BLOCKS_METADATA |
1868                                  EXT4_FREE_BLOCKS_FORGET);
1869                 ei->i_data[EXT4_DIND_BLOCK] = 0;
1870                 inode->i_blocks = 0;
1871
1872                 err = ext4_mark_inode_dirty(handle, inode);
1873                 if (err)
1874                         ext4_std_error(sb, err);
1875         }
1876
1877 errout:
1878         ret = ext4_journal_stop(handle);
1879         if (!err)
1880                 err = ret;
1881         return ret;
1882
1883 invalid_resize_inode:
1884         ext4_error(sb, "corrupted/inconsistent resize inode");
1885         return -EINVAL;
1886 }
1887
1888 /*
1889  * ext4_resize_fs() resizes a fs to new size specified by @n_blocks_count
1890  *
1891  * @sb: super block of the fs to be resized
1892  * @n_blocks_count: the number of blocks resides in the resized fs
1893  */
1894 int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count)
1895 {
1896         struct ext4_new_flex_group_data *flex_gd = NULL;
1897         struct ext4_sb_info *sbi = EXT4_SB(sb);
1898         struct ext4_super_block *es = sbi->s_es;
1899         struct buffer_head *bh;
1900         struct inode *resize_inode = NULL;
1901         ext4_grpblk_t add, offset;
1902         unsigned long n_desc_blocks;
1903         unsigned long o_desc_blocks;
1904         ext4_group_t o_group;
1905         ext4_group_t n_group;
1906         ext4_fsblk_t o_blocks_count;
1907         ext4_fsblk_t n_blocks_count_retry = 0;
1908         unsigned long last_update_time = 0;
1909         int err = 0, flexbg_size = 1 << sbi->s_log_groups_per_flex;
1910         int meta_bg;
1911
1912         /* See if the device is actually as big as what was requested */
1913         bh = sb_bread(sb, n_blocks_count - 1);
1914         if (!bh) {
1915                 ext4_warning(sb, "can't read last block, resize aborted");
1916                 return -ENOSPC;
1917         }
1918         brelse(bh);
1919
1920 retry:
1921         o_blocks_count = ext4_blocks_count(es);
1922
1923         ext4_msg(sb, KERN_INFO, "resizing filesystem from %llu "
1924                  "to %llu blocks", o_blocks_count, n_blocks_count);
1925
1926         if (n_blocks_count < o_blocks_count) {
1927                 /* On-line shrinking not supported */
1928                 ext4_warning(sb, "can't shrink FS - resize aborted");
1929                 return -EINVAL;
1930         }
1931
1932         if (n_blocks_count == o_blocks_count)
1933                 /* Nothing need to do */
1934                 return 0;
1935
1936         n_group = ext4_get_group_number(sb, n_blocks_count - 1);
1937         if (n_group >= (0xFFFFFFFFUL / EXT4_INODES_PER_GROUP(sb))) {
1938                 ext4_warning(sb, "resize would cause inodes_count overflow");
1939                 return -EINVAL;
1940         }
1941         ext4_get_group_no_and_offset(sb, o_blocks_count - 1, &o_group, &offset);
1942
1943         n_desc_blocks = num_desc_blocks(sb, n_group + 1);
1944         o_desc_blocks = num_desc_blocks(sb, sbi->s_groups_count);
1945
1946         meta_bg = ext4_has_feature_meta_bg(sb);
1947
1948         if (ext4_has_feature_resize_inode(sb)) {
1949                 if (meta_bg) {
1950                         ext4_error(sb, "resize_inode and meta_bg enabled "
1951                                    "simultaneously");
1952                         return -EINVAL;
1953                 }
1954                 if (n_desc_blocks > o_desc_blocks +
1955                     le16_to_cpu(es->s_reserved_gdt_blocks)) {
1956                         n_blocks_count_retry = n_blocks_count;
1957                         n_desc_blocks = o_desc_blocks +
1958                                 le16_to_cpu(es->s_reserved_gdt_blocks);
1959                         n_group = n_desc_blocks * EXT4_DESC_PER_BLOCK(sb);
1960                         n_blocks_count = (ext4_fsblk_t)n_group *
1961                                 EXT4_BLOCKS_PER_GROUP(sb);
1962                         n_group--; /* set to last group number */
1963                 }
1964
1965                 if (!resize_inode)
1966                         resize_inode = ext4_iget(sb, EXT4_RESIZE_INO);
1967                 if (IS_ERR(resize_inode)) {
1968                         ext4_warning(sb, "Error opening resize inode");
1969                         return PTR_ERR(resize_inode);
1970                 }
1971         }
1972
1973         if ((!resize_inode && !meta_bg) || n_blocks_count == o_blocks_count) {
1974                 err = ext4_convert_meta_bg(sb, resize_inode);
1975                 if (err)
1976                         goto out;
1977                 if (resize_inode) {
1978                         iput(resize_inode);
1979                         resize_inode = NULL;
1980                 }
1981                 if (n_blocks_count_retry) {
1982                         n_blocks_count = n_blocks_count_retry;
1983                         n_blocks_count_retry = 0;
1984                         goto retry;
1985                 }
1986         }
1987
1988         /*
1989          * Make sure the last group has enough space so that it's
1990          * guaranteed to have enough space for all metadata blocks
1991          * that it might need to hold.  (We might not need to store
1992          * the inode table blocks in the last block group, but there
1993          * will be cases where this might be needed.)
1994          */
1995         if ((ext4_group_first_block_no(sb, n_group) +
1996              ext4_group_overhead_blocks(sb, n_group) + 2 +
1997              sbi->s_itb_per_group + sbi->s_cluster_ratio) >= n_blocks_count) {
1998                 n_blocks_count = ext4_group_first_block_no(sb, n_group);
1999                 n_group--;
2000                 n_blocks_count_retry = 0;
2001                 if (resize_inode) {
2002                         iput(resize_inode);
2003                         resize_inode = NULL;
2004                 }
2005                 goto retry;
2006         }
2007
2008         /* extend the last group */
2009         if (n_group == o_group)
2010                 add = n_blocks_count - o_blocks_count;
2011         else
2012                 add = EXT4_C2B(sbi, EXT4_CLUSTERS_PER_GROUP(sb) - (offset + 1));
2013         if (add > 0) {
2014                 err = ext4_group_extend_no_check(sb, o_blocks_count, add);
2015                 if (err)
2016                         goto out;
2017         }
2018
2019         if (ext4_blocks_count(es) == n_blocks_count)
2020                 goto out;
2021
2022         err = ext4_alloc_flex_bg_array(sb, n_group + 1);
2023         if (err)
2024                 return err;
2025
2026         err = ext4_mb_alloc_groupinfo(sb, n_group + 1);
2027         if (err)
2028                 goto out;
2029
2030         flex_gd = alloc_flex_gd(flexbg_size);
2031         if (flex_gd == NULL) {
2032                 err = -ENOMEM;
2033                 goto out;
2034         }
2035
2036         /* Add flex groups. Note that a regular group is a
2037          * flex group with 1 group.
2038          */
2039         while (ext4_setup_next_flex_gd(sb, flex_gd, n_blocks_count,
2040                                               flexbg_size)) {
2041                 if (jiffies - last_update_time > HZ * 10) {
2042                         if (last_update_time)
2043                                 ext4_msg(sb, KERN_INFO,
2044                                          "resized to %llu blocks",
2045                                          ext4_blocks_count(es));
2046                         last_update_time = jiffies;
2047                 }
2048                 if (ext4_alloc_group_tables(sb, flex_gd, flexbg_size) != 0)
2049                         break;
2050                 err = ext4_flex_group_add(sb, resize_inode, flex_gd);
2051                 if (unlikely(err))
2052                         break;
2053         }
2054
2055         if (!err && n_blocks_count_retry) {
2056                 n_blocks_count = n_blocks_count_retry;
2057                 n_blocks_count_retry = 0;
2058                 free_flex_gd(flex_gd);
2059                 flex_gd = NULL;
2060                 goto retry;
2061         }
2062
2063 out:
2064         if (flex_gd)
2065                 free_flex_gd(flex_gd);
2066         if (resize_inode != NULL)
2067                 iput(resize_inode);
2068         ext4_msg(sb, KERN_INFO, "resized filesystem to %llu", n_blocks_count);
2069         return err;
2070 }